Nowadays, a higher commitment is more common in the health sector, not only from medical or government institutions, but also from the private industry and society at large.
One of the branches that has gained relevance relates to metallic elements used for the conduction and distribution of water, both in the industrial and service sector, which seeks to control material used for said purpose, thereby preventing health risks caused by substances that may be transmitted by being dissolved in water, and which may cause damage in people.
On the other hand, lead is one of the main elements contained in brass for piping, due to its machinability, lead favors the leakage and braking of shavings, working as lubricant throughout the machining process, thereby reducing temperatures during the cutting process, thereby extending the life of cutting tools; however, the same is a dangerous compound which accumulates in the nervous system and is particularly dangerous for the mental development of children.
Legislation has emerged in the United States, an example of this is California's AB 1953 Assembly Bill. This project defines the term “lead free”, for the purposes of the manufacturing, industrial processing and transmission or distribution of water for human consumption in the lead of piping and piping accessories, plumbing accessories, and accessories, to an intermediate lead content on the wet surface of piping systems and accessories of no more than 0.25% in weight, which means that a lower percentage of lead contained in the alloy strictly complies with the requirement for use in water conduction for human consumption.
In recent years, efforts directed to regulations for copper alloys containing lead have been carried out in order to drastically limit the allowable lead level in copper alloys. Consequently, fast cut low-lead copper alloys have been developed, reaching 0.02% in weight.
In the state of the art, several low-lead copper alloys have been described, such as the case of application MX/a/2014/013285, providing alloys and methods to form copper alloys, including red and yellow brass, containing sulfur and antimony; the alloy is hardened by copper, zinc, nickel and manganese precipitation, showing resistance and ductility with values similar to those of stainless steels in combination with machinability properties; application MX/a/2012/011929 refers to copper-based alloys with added manganese and sulfur and/or calcium, as well as secondary elements. Copper alloys ere free from tellurium and lead and are characterized by a high electric conductivity and utility for mechanization through shavings detachment. Patent MX 291315 B protects a fast cut copper ahoy containing a reduced amount of copper in comparison with other conventional fast cut copper alloys, with Industrial machining capacity. Fast cut alloys comprise from 71.5 to 78.5 percent of their weight in copper, from 2.0 to 4.5 percent of their weight in silicon, up to 0.005, but not more than 0.02 percent of their weight in lead and the remaining percentage of their weight of zinc; patent MX 221266 refers to: manufactured copper-based alloy components, designed to be subjected, during the production stage, to work operations carried out either through machining, molding or die casting, specifically plumbing components manufactured from brass alloy, designed to be used in drinking water systems, having said components the respective surfaces defined by said alloy designed to be exposed, throughout the using time. Copper-based alloys contain a previously determined lead quality; patent MX 204484 discloses lead free copper alloys with properties comparable with copper-based alloys with lead made from copper-based alloys containing bismuth.
In American patents U.S. Pat. No. 8,506,730, “Copper/zinc alloys having low levels of lead and good machinability”, U.S. Pat. No. 8,349,097 “Dezincification-resistant copper alloy and method for producing product comprising the same”; U.S. Pat. No. 8,239,034 “Lead free brass alloy” and U.S. Pat. No. 8,273,192 “Lead-free, bismuth-free free-cutting phosphorous brass alloy”, among other publications, which must be considered as included in the present description.
On this regard, an increasing public interest has been developed in relation to the lead content of plumbing components related to drinking water, increasing the interest in reducing the lead content even more.
Some of the attempts to reduce the lead levels in copper alloys include the introduction of other elements instead of lead, giving as result machining and finishing problems in the manufacturing process, including primary casting, primary machining, secondary machining, polished, coatings and mechanical mounting. Therefore, the need for a casting solution with a low lead alloy cast providing low cost alloys, without degradation of the mechanical or chemical properties, or a relevant interruption of the manufacturing process for the material, causing finishing and cutting problems.